Abstract : Hydrodynamical applications of the thermodynamic concept of available enthalpy, which is a restricted form of the exergy theory, are presented. The existence of a local energy cycle is demontrated. This local cycle is obtained in connection with a new concept, the potential change in total entropy, which allows such an extention of the exergy theory to atmospheric studies. This achives a synthetic view of meteorological energetics, generalizing all previous available energy concepts.